If the House of Representatives was elected through PR methods, then people would feel as their votes matter, and thus, more people would vote! A constitutional amendment is required, of course, but if, in Congress, we are to be represented accurately, then we should be represented proportionally!
From Wiki:
Proportional representation (PR) characterizes electoral systems by which divisions in an electorate are reflected proportionately in the elected body. If 30% of the electorate support a particular political party, then roughly 30% of seats will be won by that party.
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In open list proportional representation systems, parties provide a list of candidates. Voters can then rank which party members they want to vote for. As in a closed list PR system, districts do not exist.